“Gentle Giants,” by Stephen Fraser 1 Would you stick your head into the mouth of a shark as big as a whale? 2 Several years ago, Robert Hueter found himself with his head all the way inside a shark’s mouth. The fish was about 22 feet long and weighed more than 3,000 pounds. “I put my whole head and shoulders into it,” he says. Hueter is a biologist at the Mote Marine Laboratory in Sarasota, Fla. He and a colleague, Phil Motta, of the University of South Florida, were conducting research at the Georgia Aquarium. The big shark had been safely anesthetized—put in a sleeplike state. “At no time did we feel we were in any danger,” says Hueter. “It was more of a feeling of ‘Let’s not hurt the shark; let’s be very careful.’ 3 “Afterwards, Phil said to me, ‘Boy, we sure do some crazy things together!’” The animal that the two men examined was a juvenile whale shark, the biggest species of fish in the world. An adult whale shark can weigh 14 tons and be 14 meters (45 feet) long. Despite their size and abundance, whale sharks are a mystery in many ways. Filter Feeders 4 Hueter saw his first whale shark when he was a college student. “I was amazed at its size and power when it swam,” he recalls. “But I wasn’t frightened, because the animal was so gentle.” Gentle isn’t a word you would expect to see in an article about sharks, especially giant ones. Sharks have fearsome reputations. But though they’re carnivores (flesh eaters), sharks rarely attack people. “There are only a dozen or so species that have ever bitten a human,” says Hueter, “and none of them actively hunt humans as prey.” 5 The whale shark got its name because it’s as big as some whales. And, like many whales, it’s a filter feeder, an animal that strains food from the water it swallows. The food that whale sharks filter is mainly zooplankton (tiny marine animals and fish eggs). “We actually call whale sharks planktivorous, which means ‘plankton-eating,’” says Hueter. 6 A whale shark eats on the run. As it cruises through the ocean, water flows continuously into its mouth. Filter pads in its throat strain out the zooplankton, and the filtered water is expelled through the shark’s gills. The trapped food gathers in a big ball at the back of the animal’s throat before being swallowed. 7 Filter feeding mechanisms are what Hueter and Motta were studying when they stuck their heads inside the whale shark at the Georgia Aquarium. “We used a waterproof camera and photographed the inside of the animal’s mouth,” says Motta. “We were trying to figure out how the animal could gulp so much zooplankton without clogging its gills. We still are not sure.” 7Rasp Teeth 8 Although whale sharks don’t bite or chew, they have thousands of tiny teeth, each the size of a match tip, arranged in hundreds of rows. The rows resemble rasps—woodworking tools that have tiny bumps arranged along a metal blade. The whale shark’s Latin name, Rhincodon typus, means “rasp tooth type.” Hueter believes the teeth are vestigial, an evolutionary leftover from the whale shark’s ancestor. 9 That ancestor was probably a creature similar to today’s nurse shark, a 135-kilogram (300-pound) species that often rests on the seabed and feeds on fish and other marine animals there. Hueter guesses that the whale shark’s ancestor originally ate fish eggs but eventually took advantage of the nutritional benefits of zooplankton in the open sea. 10 Zooplankton can be so abundant in the whale shark’s feeding grounds, adds Motta, that visibility in the water is limited to 3 to 4.5 meters (10 to 15 feet). “When a whale shark suddenly appears ahead, it’s like confronting a school bus underwater,” he says. 11 Whale sharks are also distinctive for being aplacentally viviparous. Their pups hatch from eggs inside the mother’s body and continue to develop there, feeding on yolk and nutritional liquid, until they are born alive. By contrast, some sharks have a placenta, an organ that provides oxygen and nourishment to the pups inside the mother’s body. Other, less advanced shark species lay eggs on the ocean floor, and the fetuses develop for weeks before hatching. “There is no parental care in any shark species,” says Hueter. “The offspring are strictly on their own after they are born.” Mystery List 12 Hundreds of thousands of whale sharks are thought to populate the oceans in a band of tropical waters that circles the globe. In 2007, Hueter and his colleagues attached a tracking device to an adult whale shark that they had named Rio Lady. In 150 days, she traveled nearly 8,000 kilometers (5,000 miles) from Mexico’s Yucatán Peninsula southeast to a point halfway between Brazil and Africa. Hueter suspects that whale sharks give birth there. 13 That’s one mystery among many that scientists are investigating. “Whale sharks dive deeper than a mile,” adds Hueter. “We don’t know why they do that, or where they mate, or how long they live. And then there’s the question of how they ingest so much zooplankton without clogging their gills. The list goes on.” 13*Please complete questions 8-13 before writing the essay.

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You have read two texts that inform the reader about science and the natural world. Both texts include the reactions of people—one a young boy and the other scientists—as they learn and work. What can these texts tell us about the role of curiosity, questioning, or imagination in science? Write an informative essay that explains how these traits promote knowledge and learning. Be sure to cite evidence from one or both articles.